CN109153005B

CN109153005B - Gas separation process

Info

Publication number: CN109153005B
Application number: CN201680080954.5A
Authority: CN
Inventors: 邢华斌; 崔希利; M.扎沃罗特科; 陈凯杰; B.陈
Original assignee: Zhejiang University ZJU; University of Limerick; University of Texas at San Antonio
Current assignee: Zhejiang University ZJU; University of Limerick; University of Texas at San Antonio
Priority date: 2016-02-02
Filing date: 2016-02-02
Publication date: 2021-08-13
Anticipated expiration: 2036-02-02
Also published as: WO2017132816A1; US20190054413A1; EP3411140A1; CN109153005A; EP3411140A4; EP3411140B1; US11058985B2

Abstract

The present invention relates to a method for separating acetylene from a gas mixture comprising acetylene. The method involves the use of a hybrid porous material having an affinity for acetylene adsorption. The hybrid porous material comprises a metal species (M) and a first linking group (L)¹) And a second linking group (L)²) Wherein the metal species (M) is linked via a first linking group (L)¹) Are linked together in a first and a second orientation and via a second linking group (L)²) Are joined together in a third direction to form the three-dimensional structure. The hybrid porous material may have a high selectivity for acetylene and/or a high acetylene adsorption capacity. The method may be particularly useful for purifying ethylene gas contaminated with acetylene during an ethylene production/purification process. The method may be particularly useful for large scale separation of acetylene from other gases such as ethylene and carbon dioxide during acetylene production/purification processes.

Description

Gas separation process

The present invention relates to a method for separating acetylene from a gas mixture comprising acetylene. In particular, the invention relates to the separation of acetylene from a gas mixture comprising acetylene and ethylene and/or a gas mixture comprising acetylene and carbon dioxide and/or a gas mixture comprising acetylene, ethylene and carbon dioxide. The invention also relates to the use of the hybrid porous material for separating acetylene from a gas mixture comprising acetylene.

Gases are important industrial commodities and fuels, and their importance is increasing, as described in "ports Materials and the Age of the Gas" (Kitagawa, S., Angew. chem. int. Ed.2015, 54, 10686-. However, purification, separation, isolation, storage, and sensing of various important gases present a number of technical challenges. For example, ethylene is an important raw chemical in polymer production, but it has proven difficult to purify ethylene to the desired high purity in an efficient manner, particularly by removing acetylene.

Known methods of separating/purifying acetylene and ethylene, such as solvent extraction, distillation and partial hydrogenation of acetylene, involve highly energy-consuming and expensive processes. Therefore, there is a need to develop efficient processes for the selective separation of acetylene and ethylene. There is also a need to develop efficient processes for selectively separating acetylene from ethylene and other gases that may be present in the gas mixture during the production of acetylene, such as other hydrocarbons (other than acetylene and ethylene) and carbon dioxide.

A great deal of research has been conducted on methods of separating/purifying gas mixtures using porous materials, which have focused on zeolites, metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs). However, many known methods involve a trade-off between physical adsorption capacity (referred to as working capacity) and selectivity for the target gas, with high selectivity materials providing poor adsorption capacity and materials with high adsorption capacity providing poor selectivity.

For example, MOFs described in "Hydrocarbon Separations in a Metal-Organic Framework with Open ion (II) Coordination Sites" (E.D. Bloch et al, Science, 2012,335,1606-1610) can adsorb relatively large amounts of acetylene gas, but provide relatively poor selectivity of separation.

The MOFs described in "display of Metal Organic and Organic light to tube Micropores with in Isostactic devices Mixed-Metal Organic Frameworks (M' MOFs) for the high selectivity Separation of Chiral and Achiral Small Molecules" (M.C. Das et al, J. Am. chem. Soc., 2012, 134, 8703-8710) have a relatively high selectivity for acetylene, but adsorb only Small amounts of gas.

The inability to achieve both high capacity and high selectivity has been a major obstacle to the development of efficient gas separation techniques using MOFs.

It is an object of the present invention to provide a method, use or material that addresses at least one of the disadvantages of the prior art, whether identified herein or elsewhere, or to provide an alternative to existing methods, uses or materials. For example, it is an object of embodiments of the present invention to provide a process for separating acetylene from a gas mixture comprising acetylene with a high selectivity for acetylene and/or a high capacity for acetylene adsorption. It is another object of embodiments of the present invention to provide such a method that can be performed at about ambient temperature and/or pressure.

According to a first aspect of the present invention there is provided a method of separating acetylene from a gas mixture comprising acetylene, the method comprising contacting the gas mixture with a mixing porous material;

wherein the mixed porous material comprises a three-dimensional lattice of metal species (M) and linking groups;

wherein the metal species (M) is linked via a first linking group (L)¹) Linked together in a first dimension and a second dimension and through a second linking group (L)²) Connected together in a third dimension to form a three-dimensional lattice; and is

Wherein L is¹And L²Is an organic linking group, and L¹And L²Is an inorganic linking group.

Suitably, the hybrid porous material has the following chemical formula: m (L)¹)₂(L²)。

Suitably, the metal species (M) is a transition metal atom or ion.

Suitably, the metal species (M) is a first row transition metal atom or ion.

Suitably, the metal species (M) is selected from atoms or ions of Cu, Zn and Ni.

In some preferred embodiments, the metal species (M) is Cu ions. Preferably, the metal species (M) is Cu²⁺Ions.

In some preferred embodiments, the metal species (M) is a Ni ion. Preferably, the metal species (M) is Ni²⁺Ions.

Suitably, all the metal species (M) in the mixed porous material are the same.

Alternatively, the metal species (M) in the mixed porous material may comprise at least two different metal species (M) suitably selected from atoms or ions of Cu, Zn and Ni.

In the mixed porous material used in the method of the first aspect of the present invention, the metal species (M) is linked through the first linking group (L)¹) Connected together in a first dimension and a second dimension.

L¹And L²Is an organic linking group, and L¹And L²Is an inorganic linking group. In other words, the first linking group (L)¹) Is an organic linking group, and a second linking group (L)²) Is an inorganic linking group, or a first linking group (L)¹) Is an inorganic linking group, and a second linking group (L)²) Is an organic linking group.

Thus, the first linking group (L)¹) Either an organic or inorganic linker. Suitably, the first linking group (L)¹) Is an organic linking group. Preferably, the first linking group (L)¹) Comprising at least two donor atoms. The donor atom is an atom present within the linking group that has a lone electron pair that may contribute, for example, in the formation of a metal-ligand complex. The lone electron pair suitably contributes to the metal species when forming the mixed porous material. The donor atom may be a charged or neutral species, e.g. the donor atom may actually act as an ion such as O^-Are present.

Suitably, the donor atom in the organic linking group is selected from halogen, oxygen and nitrogen. Suitable organic linkers may comprise N-oxide groups that provide oxygen donor atoms. The two or more donor atoms may each be the same or different.

Suitably, the donor atom is selected from oxygen and nitrogen.

Preferably, all donor atoms are nitrogen.

Suitably, the first linking group (L)¹) Is a nitrogen ligand comprising at least two donor atoms which are nitrogen atoms. Suitably, the at least two nitrogen atoms each comprise a lone pair of electrons suitable for binding to the metal species. Thus, the nitrogen ligand is suitably bisA linked nitrogen ligand. By "doubly linked" is meant that the nitrogen ligand is capable of binding to two different metal species (M) in the mixed porous material. In a preferred embodiment, the lone pairs of electrons on the two nitrogen atoms are oriented away from each other in the orbital at an angle capable of forming a crystal lattice, such as at an angle of, for example, greater than 90 °, for example, an angle of about 120 ° or an angle of about 180 °.

Suitably, the two nitrogen atoms in the doubly-linked nitrogen ligand are separated by a distance of from 2.5A to 20A, for example from 2.5A to 10A or from 10A to 20A.

Suitably, the first linking group (L)¹) Is a doubly linked nitrogen ligand. Preferred doubly-linked nitrogen ligands comprise at least one nitrogen-containing heterocycle. In some embodiments, the doubly linked nitrogen ligand may be a nitrogen-containing heterocycle that includes two nitrogen atoms each having a lone pair of electrons, such as pyrazine.

In some embodiments, the doubly linked nitrogen ligand comprises two nitrogen-containing heterocycles. The two nitrogen-containing heterocycles may be linked together by a bond. One such preferred doubly linked nitrogen ligand is 4,4' -bipyridine.

Alternatively, the two nitrogen-containing heterocycles may be linked together by a spacer group, such as acetylene. One such preferred doubly-linked nitrogen ligand is 4,4 '-dipyridylacetylene (4,4' -dipyridylacetylene). Suitably, the first linking group (L)¹) Is a doubly linked nitrogen ligand having the formula (L2N):

wherein R is¹Is an optionally substituted linking group.

R¹May be a heteroatom, a group of attached heteroatoms or a heteroatom containing group. For example, R¹May be a-N = N-group.

R¹May be a hydrocarbon group. The hydrocarbyl group may comprise a cyclic group. The hydrocarbyl group may comprise an aromatic cyclic group. The hydrocarbyl group may comprise a heterocyclic group.

As used herein, the term "hydrocarbyl" is used in its ordinary sense, as is well known to those skilled in the art. In particular, it refers to groups having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:

(i) hydrocarbyl, that is, aliphatic substituents (which may be saturated or unsaturated, straight or branched chain, e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring);

(ii) substituted hydrocarbyl, i.e., substituents containing non-hydrocarbyl groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent (e.g., halogen (especially chlorine and fluorine), hydroxy, alkoxy, ketone, acyl, cyano, mercapto, alkylmercapto, amino, alkylamino, nitro, nitroso, and sulfoxy);

(iii) hetero substituents, that is, substituents which, while predominantly hydrocarbon in character, in the context of the present invention contain non-carbon atoms in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl.

Suitable doubly-linked nitrogen ligands may be selected from 4,4' -bipyridinylacetylene and compounds (LA) to (LI):

。

suitably, the first linking group (L)¹) Is a doubly linked nitrogen ligand selected from the group consisting of pyrazine, 4 '-bipyridine and 4,4' -bipyridinylacetylene. Preferably, the first linking group (L)¹) Selected from the group consisting of 4,4 '-bipyridinylacetylene and 4,4' -bipyridine.

Suitably, all first linking groups (L) in the porous material are mixed¹) Are the same.

The metal species (M) being bound via a first linking group (L)¹) Connected together in a first dimension and a second dimension. Suitably, the first and second dimensions are substantially perpendicular to each other. Suitably, the first linking group (L)¹) Joining together metal species (M) to form a two-dimensional layer having square planar repeating units of formula (I):

。

in the mixed porous material used in the method of the first aspect, the metal species (M) passes through the second linking group (L)²) Joined together in the third dimension to form a three-dimensional lattice.

Suitably, a second linking group (L)²) An interaction can be formed between two different metal species. Generally, metal speciesTo have a first linking group (L)¹) For example, a two-dimensional layer of square planar repeating units of formula (I).

Suitably, a second linking group (L)²) Forming interactions with two different metal species in two different layers.

Suitably, a second linking group (L)²) Capable of forming an interaction with two different atoms or ions of the metal species (M) to form a three-dimensional lattice.

For example, a second linking group (L)²) Capable of forming an interaction with two different atoms or ions of the metal species (M), which are oriented at an angle of more than 90 °, for example at an angle of about 120 ° or at an angle of about 180 ° with respect to each other.

Preferably, the second linking group (L)²) Is an inorganic linking group.

Suitably, each second linking group (L)²) Comprising at least two donor atoms. Suitable donor atoms include halogens, oxygen, nitrogen and sulfur. Second linking group (L)²) Preferred donor atoms of (a) are halogen, in particular chlorine or fluorine, preferably fluorine.

Suitably, a second linking group (L)²) Comprising at least one halogen atom. Preferably, the second linking group (L)²) Containing at least one fluorine atom.

Suitably, a second linking group (L)²) Is an inorganic compound containing at least one fluorine atom. Suitably, a second linking group (L)²) Is charged, suitably anionic. Suitably, a second linking group (L)²) Is an inorganic anion containing at least one fluorine atom.

Preferably, the second linking group (L)²) Comprising at least two halogen atoms. Preferably, the second linking group (L)²) Comprising at least two fluorine atoms.

Suitably, a second linking group (L)²) Is of the formula AX_n ^y-Wherein X is selected from F or Cl, n is an integer from 2 to 6, y is an integer from 0 to 2, and A is selected from Si, Ti, Sn, Zr or Ge. Suitably, n isAn integer of 4 to 6. Preferably, n is 6. Preferably, y is 2. Preferably, X is F.

Preferably, the second linking group (L)²) Selected from SiF₆ ^2-、TiF₆ ^2-、SnF₆ ^2-、ZrF₆ ^2-And GeF₆ ^2-。

Preferably, the second linking group (L)²) Selected from SiF₆ ^2-、TiF₆ ^2-And SnF₆ ^2-。

Preferably, the second linking group (L)²) Is SiF₆ ^2-Ions.

Preferably, the second linking group (L)²) Is TiF₆ ^2-Ions.

Preferably, the second linking group (L)²) Is SnF₆ ^2-Ions.

Preferably, the second linking group (L)²) Is ZrF₆ ^2-Ions.

Preferably, the second linking group (L)²) Is GeF₆ ^2-Ions.

Suitably, all second linking groups (L) in the porous material are mixed²) Are all the same.

Suitably, a second linking group (L)²) Connecting different two-dimensional layers of metal species (M) having square planar repeating units of formula (I) to form a three-dimensional lattice.

Suitably, the three-dimensional lattice of the metal species (M) and the linking group has a cubic lattice structure, suitably a primary cubic lattice structure.

Suitably, the metal species (M) and the linking group (L)¹And L²) The three-dimensional lattice of (a) comprises repeating units (unit cells) of formula (II):

。

suitably, the three-dimensional lattice of metal species (M) and linking groups consists essentially of repeat units of formula (II).

Suitably, the metal species (M) is selected from Cu²⁺、Ni²⁺And Zn²⁺Ion, first linking group (L)¹) Selected from the group consisting of 4,4 '-bipyridinylacetylene, 4' -bipyridine and pyrazine, and a second linking group (L)²) Selected from SiF₆ ^2-、TiF₆ ^2-、SnF₆ ^2-、ZrF₆ ^2-And GeF₆ ^2-。

Preferably, the metal species (M) is selected from Cu²⁺、Ni²⁺And Zn²⁺Ion, first linking group (L)¹) Selected from the group consisting of 4,4 '-bipyridinylacetylene, 4' -bipyridine and pyrazine, and a second linking group (L)²) Selected from SiF₆ ^2-、TiF₆ ^2-And SnF₆ ^2-Ions.

Suitably, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Selected from the group consisting of 4,4 '-bipyridinylacetylene and 4,4' -bipyridine, and a second linking group (L)²) Is SnF₆ ^2-Ions.

The mixed porous material used in the method of the first aspect may be prepared by any suitable method, for example by solid state synthesis, crystallization from a suitable solvent, direct mixing or mechanochemical, each with or without heat. For example, the mixed porous material can be prepared by any of the methods described above by reacting approximately equimolar amounts of a metal species (M), such as a salt of the metal species (M), the first linking group (L)¹) E.g. a doubly linked nitrogen ligand and a second linking group (L)²) E.g. AX_n ^y-Salts of the anions, optionally together in a suitable solvent, e.g. a mixture of water and methanol, optionally with heating.

In some embodiments, the metal species (M) and the linking group (L)¹And L²) May interpenetrate. Interpenetrating means that the two or more three-dimensional lattices of the metal species (M) and the linking group have interlocked such that they do not break chemical bondsCannot be separated, for example, as shown in structure (III), where the first three-dimensional lattice comprises M, L¹And L²And the second three-dimensional lattice comprises M', L^1’And L^2’：

。

Whether a mixed porous Material forming reaction such as those described above forms an interpenetrating mixed porous Material or a non-interpenetrating mixed porous Material may depend on the particular reaction type and/or solvent used (if used) and/or the Temperature of the reaction and/or the Concentration of the reaction mixture, as described in "Temperature and Concentration Control over interaction in a Metal-Organic Material" (zawortko, m.j. et al, j. Am. chem. soc., 2009, 131, 17040-17041) and "Temperature-directed synthesis of Metal-Organic Material" (zawortko, m.j. and Zhang, z., chem.soc. rev., 2014, 43, 5444).

The three-dimensional lattice of metal species (M) and linking groups comprises pores, said three-dimensional lattice providing a hybrid porous material for use in the method of the first aspect. The hole is formed at M, L¹And L²Formed in portions of a defined three-dimensional lattice. Thus, in this process, acetylene can be passed through the reactor from M, L¹And L²The openings of the pores in the hybrid porous material are defined and bound to the three-dimensional lattice within the pores. It is believed that the size of the pores may contribute to the selectivity and capacity exhibited by the composite porous material of the present invention.

Suitably, the mixed porous material comprises pores having an effective pore diameter from 3.5 a to 12 a.

The effective pore size may additionally or alternatively be defined as the effective pore diameter. The effective pore size/diameter is a measure of the pore size at the narrowest point of the pore. These values take into account the van der waals radii of the atoms lining the pore walls (i.e., they are not interatomic distances).

In alternative embodiments, the first linking group (L)¹) Is an inorganic linking group and is as described above for the second linking group (L)²) Defined, and second connectionGroup (L)²) Is an organic linking group and is as described above for the first linking group (L)¹) As defined. In other words, in the mixed porous material used in the method of the first aspect, the first linking group (L)¹) And a second linking group (L)²) The above definitions of (a) may be interchanged.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridylacetylene, second linking group (L)²) Is SiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are interpenetrating. This particular hybrid porous material may be referred to as SIFSIX-2-Cu-i.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridylacetylene, second linking group (L)²) Is TiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are interpenetrating. This particular hybrid porous material may be referred to as TIFSIX-2-Cu-i.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridylacetylene, second linking group (L)²) Is SnF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are interpenetrating. This particular hybrid porous material may be referred to as SNFSIX-2-Cu-i.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Ni²⁺Ion, first linking group (L)¹) Is pyrazine, second linking group (L)²) Is SiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are not interpenetrating. This particular hybrid porous material may be referred to as SIFSIX-3-Ni.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridine, the second linking group (L)²) Is SiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are not interpenetrating. This particular hybrid porous material may be referred to as SIFSIX-1-Cu.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Cu²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridylacetylene, second linking group (L)²) Is SiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are not interpenetrating. This particular hybrid porous material may be referred to as SIFSIX-2-Cu.

In a preferred embodiment of the process of the first aspect, the metal species (M) is Zn²⁺Ion, first linking group (L)¹) Is pyrazine, second linking group (L)²) Is SiF₆ ^2-The ions, and the three-dimensional lattice of metal species (M) and linking groups are not interpenetrating. This particular hybrid porous material may be referred to as SIFSIX-3-Zn.

Without being bound by theory, it is believed that the hybrid porous material used in the method of the present invention can act as an effective acetylene trap because the material has pore size (effective pore size) and pore chemistry that are complementary to acetylene and favor acetylene adsorption. These materials can provide excellent acetylene selectivity and capacity.

In a preferred embodiment, the mixed porous material used in the method of the invention comprises a second linking group (L)²) A second linking group (L)²) Is an inorganic compound containing at least one fluorine atom. Without being bound by theory, it is believed that the acetylene molecule is predominantly formed by, for example, reacting acetylene with SiF₆ ^2-Strong C-h.. F hydrogen bond (bond length 2.017 a) adsorption between. It is believed that another important interaction to ensure that the mixed porous material adsorbs acetylene is the acetylene with the first linking group (L)¹) Such as van der waals interactions between 4,4' -bipyridine. For example, each crystal unit cell of SIFSIX-1-Cu contains four equivalent exposed F atoms with lone pairs of electrons on the same horizontal plane, and itThe channel pore size is large enough to bind one acetylene molecule per exposed F atom. In addition, adjacent adsorbed C₂H₂The distance between them is ideal for the acetylene molecules to interact with each other through multiple H δ +. C δ -dipole interactions (which may be referred to as guest-guest interactions) and further enhance adsorption in the material.

In which the second linking group (L)²) Is SiF₆ ^2-In embodiments of (a), it is believed that the weakly basic SiF is₆ ^2-The (pKa = 1.92) site primarily initiates the binding of the acetylene molecule. Acetylene (pKa = 25) is more acidic than ethylene (pKa = 44), and thus SiF is more acidic than ethylene₆ ^2-Stronger interaction with acetylene is formed (e.g., Δ E in SIFSIX-1-Cu: 44.6 kJ/mol for acetylene and 27.2 kJ/mol for ethylene). This is believed to contribute to the selectivity of acetylene to ethylene in the process of the first aspect. The same reasoning can be applied to an optional second linking group (L) which is also weakly basic²) E.g. TiF₆ ^2-、SnF₆ ^2-、ZrF₆ ^2-And GeF₆ ^2-。

The method of the first aspect comprises separating acetylene from a gas mixture comprising acetylene. Suitably, separating acetylene from the acetylene containing gas mixture comprises adsorbing acetylene onto the surface of the mixed porous material. Suitably, acetylene is absorbed onto the inner surface, suitably onto the inner surface of the pores of the hybrid porous material.

Suitably, the acetylene adsorbed onto the surface of the mixed porous material may subsequently be desorbed from the mixed porous material and may therefore be obtained at a higher purity than is present in the gas mixture containing acetylene.

Suitable desorption methods are known in the art and may include the use of reduced pressure (vacuum desorption), the use of heated carrier gases such as nitrogen or hydrogen and the use of heat (above ambient but below 120 ℃).

The method of the first aspect may include using a mixed porous material in a fixed bed purification/separation process, wherein the mixed porous material provides a fixed bed filtration media.

The method of the first aspect may comprise using a mixed porous material as part of the purification/separation membrane.

Suitably, the gas mixture comprises ethylene. Suitably, the gas mixture comprises acetylene and ethylene. Suitably, the gas mixture consists essentially of acetylene and ethylene.

The gas mixture may be wet or dry. In other words, the gas mixture may contain water vapor or may be substantially free of water vapor.

In some embodiments, the process can be used to purify ethylene gas contaminated with acetylene, and thus relatively small amounts of acetylene can be removed from the contaminated ethylene gas. In such embodiments, the gas mixture may be contaminated ethylene.

In such embodiments, the hybrid porous material (hybrid porous) may be SIFSIX-2-Cu-i (i.e., wherein the metal species (M) is Cu)²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridylacetylene, second linking group (L)²) Is SiF₆ ^2-The ions and the three-dimensional lattice of metal species (M) and linking groups are interpenetrating). The inventors found that SIFSIX-2-Cu-i was particularly effective in this method.

In such embodiments, the contaminated ethylene may comprise from 0.001 wt% to 5 wt%, preferably from 0.01 wt% to 4 wt%, preferably from 0.05 wt% to 3 wt%, suitably from 0.1 wt% to 2 wt%, for example from 0.5 wt% to 1.5 wt% acetylene.

In such embodiments, the gas mixture may comprise an acetylene to ethylene ratio of from 0.1:99.9 to 10:90, for example from 1:99 to 5: 95.

In such embodiments, the contaminated ethylene may comprise other low molecular weight hydrocarbons, such as methane, ethane, propylene, and propane.

In some embodiments, the process can be used to provide a large (e.g., large scale) separation of acetylene from ethylene to provide a relatively large amount of high purity acetylene.

In such embodiments, the hybrid porous material may beSIFIX-1-Cu (i.e., wherein the metal species (M) is Cu)²⁺Ion, first linking group (L)¹) Is 4,4' -bipyridine, the second linking group (L)²) Is SiF₆ ^2-Ions, and the three-dimensional lattice of metal species (M) and linking groups is not interpenetrating). The inventors found that SIFSIX-1-Cu was particularly effective in this method.

In such embodiments, the gas mixture may comprise an acetylene to ethylene ratio of from 1:9 to 9:1, suitably from 1:4 to 4:1, suitably from 3:7 to 7:3, for example from 4:6 to 6: 4.

In such embodiments, the gas mixture may comprise an acetylene to ethylene ratio of 4:6 to 9: 1.

In such embodiments, acetylene and ethylene may be combined to provide a gas mixture of up to 90 volume%, suitably up to 80 volume%, for example up to 70 volume%.

In such embodiments, the gas mixture may comprise other components, such as alkanes (paraffins), carbon dioxide, carbon monoxide, other alkynes (other than acetylene), other alkenes (other than ethylene), and dienes.

The contacting of the gas mixture with the hybrid porous material may be performed at any suitable temperature below 120 c, at which the risk of acetylene explosion is very high.

Suitably, the method of the first aspect may be carried out at ambient temperature. The method can operate efficiently at ambient temperatures to save cost and/or energy and represents a significant advantage over some methods of the prior art.

Suitably, the contacting of the gas mixture with the mixed porous material is carried out at a temperature of from-20 ℃ to 60 ℃, suitably from 0 ℃ to 50 ℃, suitably from 10 ℃ to 40 ℃.

In some embodiments, contacting the gas mixture with the mixed porous material is performed at a pressure of 0.5 bar to 2 bar.

In some alternative embodiments, the contacting of the gas mixture with the mixed porous material is carried out at an acetylene partial pressure of less than 0.1 bar.

Suitably, the process of the first aspect is carried out at ambient pressure. The method can operate efficiently at ambient pressure saving cost and/or energy and avoiding the use of complex equipment, thus providing significant advantages over some methods of the prior art.

According to a second aspect of the present invention, there is provided the use of a hybrid porous material for separating acetylene from a gas mixture comprising acetylene;

Preferred features of the second aspect are as defined in relation to the first aspect.

The use of this second aspect may be, for example, the purification of ethylene gas contaminated with acetylene during an ethylene production/purification process. In this use, the hybrid porous material may be SIFIX-2-Cu-i.

The use of this second aspect may be, for example, the separation of acetylene from ethylene on a relatively large scale during an acetylene production/purification process. In such a use, the hybrid porous material may be SIFSIX-1-Cu.

The use of this second aspect may be for separating acetylene from ethylene and carbon dioxide and optionally other gases on a relatively large scale, for example during an acetylene production/purification process. In such a use, the hybrid porous material may be SIFSIX-1-Cu.

According to a third aspect of the present invention, there is provided a hybrid porous material comprising a three-dimensional lattice of metal species (M) and linking groups;

wherein the metal species (M) is linked via a first linking group (L)¹) Linked together in a first dimension and a second dimension and through a second linking group: (L²) Joined together in a third dimension to form a three-dimensional lattice.

Preferred features of the third aspect are as defined above in relation to the first and second aspects.

In a preferred embodiment, the second linking group (L)²) Is of the formula AX_n ^y-Wherein X is selected from F or Cl, n is an integer from 2 to 6, y is an integer from 0 to 2, and A is selected from Si, Ti, Sn, Zr or Ge. Suitably, n is an integer from 4 to 6. Preferably, n is 6. Preferably, y is 2. Preferably, X is F.

Suitably, a second linking group (L)²) Selected from SiF₆ ^2-、TiF₆ ^2-、SnF₆ ^2-、ZrF₆ ^2-And GeF₆ ^2-。

The present invention may provide an improved method for separating acetylene from a gas mixture, such as a gas mixture of acetylene and ethylene.

The process of the present invention can be used to provide acetylene and/or ethylene of higher purity than prior art processes.

The process of the invention can be energy efficient and therefore cost effective.

In particular, the present invention can provide a process for removing relatively small amounts of acetylene from ethylene gas to provide high purity ethylene needed in some applications, such as in polymer production, in a cost effective and energy efficient manner.

The hybrid porous materials used in the present invention can provide significantly greater acetylene adsorption capacity than prior art materials while maintaining a high degree of selectivity with respect to ethylene.

Thus, the present invention can be used to separate acetylene from a gas mixture containing relatively large amounts of acetylene and ethylene, such as a 50:50 mixture of acetylene and ethylene.

The invention will now be described by reference to the figures and examples.

In the following examples, the following single crystal X-ray diffractometers were used to obtain single crystal X-ray structures: bruker Quest diffractometer equipped with a CMOS detector and a 1 uS microfocus Cu X-ray source.

The purity of the samples was verified using the following powder diffractometer: PANalytical X 'Pert MPD Pro with a 1D X' Celerator strip detector using Cu ka radiation.

The adsorption isotherms were collected using the following gas adsorption instrument: micromeritics Tristar II 3030 and 3Flex 3500 surface texture Analyzer.

The samples were degassed (for activation) using the following degassing instrument: micromeritics Smart VacPrep gas adsorption sample preparation device.

Example 1: SIFIX-2-Cu-i

Synthesis of SIFSIX-2-Cu-i

A solution of 4,4' -bipyridinylacetylene (0.286 mmol) in methanol (4.0 ml) was mixed with Cu (BF)₄)₂∙xH₂O (0.26 mmol) and (NH)₄)₂SiF₆(0.26 mmol) of an aqueous solution (4.0 ml) were mixed, followed by heating at 85 ℃ for 12 hours. The resulting green microcrystalline solid SIX-2-Cu-i was harvested by filtration.

Structure of (1)

SIFIX-2-Cu-i is a dual interpenetrating network comprising two SISIX-2-Cu mixed porous materials. In each of these two SIFSIX-2-Cu metal-organic frameworks, the copper cation and the 4,4' -bipyridinylacetylene ligand form a two-dimensional (2D) layer, which is formed from SiF₆ ^2-Three-dimensional (3D) hybrid porous materials of the original cubic topology of anionic pillared (pilar). "pillared" means SiF₆ ^2-The anion provides a link between the copper cation and the 2D layer of 4,4' -bipyridylacetylene ligand to provide a 3D metal-organic framework. The independent mixed porous materials are interpenetrating in a staggered manner, providing one-dimensional (1D) channels having pores with an effective pore diameter of 5a to 6 a. Inorganic column SiF₆ ^2-Exposed on the inner surface of the hole and promoting the contact with C₂H₂Strong interaction of (a). FIG. 1A shows a single mixed porous material of SIFSIX-2-Cu, which when formed into an interpenetrating structure according to the experimental method described above, results in the SISIIX-2-Cu-i shown in FIG. 1B.

Pure gas adsorption study

C of SIFSIX-2-Cu-i collected at 273K and 298K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 2A, SIFSIX-2-Cu-i vs. C₂H₂Absorption ratio of C₂H₄More particularly in the low pressure region. C at 298K, measured at 0.025 bar and 1 bar respectively₂H₂The absorptions of (a) were 2.1 mmol/g and 3.9 mmol/g. Under the same conditions, C was measured₂H₄The absorption was only 0.15 mmol/g and 2.0 mmol/g. By using the Clausius-Clapeyron equation, C₂H₂The equivalent heat (isospecific heat) (adsorption energy-Qst) was calculated to be 52.7 kJ/mol, much higher than C₂H₄35.1 kJ/mol as shown in FIG. 2B.

Powder X-ray diffraction (PXRD) and stability data

SIFIX-2-Cu-i prepared according to the above method was tested for stability to humidity by exposing SISISIX-2-Cu-i to 75% humidity and 40 ℃ for 1 day and 14 days. The PXRD pattern of the sample after the humidity test (see fig. 3A) was the same as the PXRD pattern obtained for the original sample (before the humidity test). C of exposed and original sample₂H₂The isotherms (FIG. 3B) show that SIFSIX-2-Cu-i is stable to humidity and its adsorption behavior is not affected by exposure to humidity.

Example 2: TIFSIX-2-Cu-i

Synthesis of TIFSIX-2-Cu-i

A solution of 4,4' -bipyridinylacetylene (0.286 mmol) in methanol (4.0 ml)) And Cu (BF)₄)₂∙xH₂O (0.26 mmol) and (NH)₄)₂TiF₆(0.26 mmol) of an aqueous solution (4.0 ml) were mixed, followed by heating at 85 ℃ for 12 hours. The resulting green microcrystalline solid TIFSIX-2-Cu-i was harvested by filtration.

Structure of (1)

TIFSIX-2-Cu-i is a dual interpenetrating network comprising two TIFSIX-2-Cu metal-organic frameworks. In each of these two TIFSIX-2-Cu metal-organic frameworks, the copper cation and the 4,4' -bipyridinylacetylene ligand form a 2D layer, which is formed of TiF₆ ^2-3D hybrid porous material of original cubic topology of anionic pillared. The independent mixed porous materials are interpenetrating in a staggered manner, providing 1D channels having pores with an effective pore diameter of 5a to 6 a. Inorganic post TiF₆ ^2-Exposed on the inner surface of the hole and promoting the contact with C₂H₂Strong interaction of (a). FIG. 4A shows a single hybrid porous material of TIFSIX-2-Cu, which when formed into an interpenetrating structure according to the experimental method described above, forms the TIFSIX-2-Cu-i shown in FIG. 4B.

Pure gas adsorption study

Obtaining C of TIFSIX-2-Cu-i at 273K and 298K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 5A, TIFSIX-2-Cu-i is paired with C₂H₂Absorption ratio of C₂H₄More particularly in the low pressure region. C at 298K, measured at 0.025 bar and 1 bar respectively₂H₂The absorptions of (a) were 2.2 mmol/g and 4.1 mmol/g. Under the same conditions, C was measured₂H₄The absorption was only 0.22 mmol/g and 2.5 mmol/g. By using the Clausius-Clapeyron equation, C₂H₂The equivalent heat (adsorption energy-Qst) was calculated to be 46.3 kJ/mol, which is much higher than C₂H₄35.9 kJ/mol as shown in FIG. 5B.

Powder X-ray diffraction (PXRD) and stability data

The stability to humidity of the TIFSIX-2-Cu-i prepared according to the above method was tested by exposing the TIFSIX-2-Cu-i to 75% humidity and 40 ℃ for 14 days. PXRD Pattern of samples after humidity test (see FIG. 6A) andthe PXRD patterns obtained for the original samples (before humidity testing) were identical. C of exposed and original sample₂H₂The isotherm (FIG. 6B) shows that TIFSIX-2-Cu-i is stable to humidity and its adsorption behavior is not affected by exposure to humidity.

Example 3: SNFSIX-2-Cu-i

Synthesis of SNFSIX-2-Cu-i

A solution of 4,4' -bipyridinylacetylene (0.286 mmol) in methanol (4.0 ml) was mixed with Cu (BF)₄)₂∙xH₂O (0.26 mmol) and (NH)₄)₂SnF₆(0.26 mmol) of an aqueous solution (4.0 ml) were mixed, followed by heating at 85 ℃ for 12 hours. The resulting green microcrystalline solid SNFSIX-2-Cu-i was harvested by filtration.

Structure of (1)

SNFSIX-2-Cu-i is a dual interpenetrating network comprising two SNFSIX-2-Cu metal-organic frameworks. In each of these two SNFSIX-2-Cu metal-organic frameworks, the copper cation and the 4,4' -bipyridyl acetylene ligand form a two-dimensional (2D) layer, which is formed of SiF₆ ^2-Three-dimensional (3D) hybrid porous materials of the original cubic topology of anionic pillared. The independent mixed porous materials are interpenetrating in a staggered manner, providing 1D channels having pores with an effective pore diameter of 5a to 6 a. Inorganic post SnF₆ ^2-Exposed to the pore surface and promoted with C₂H₂Strong interaction of (a). FIG. 7A shows a single mixed porous material of SNFSIX-2-Cu, which when formed into an interpenetrating structure according to the experimental method described above, forms SNFSIX-2-Cu-i shown in FIG. 7B.

Pure gas adsorption study

Collecting C of SNFSIX-2-Cu-i at 273K and 298K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 8A, SNFSIX-2-Cu-i is paired with C₂H₂Absorption ratio of C₂H₄More particularly in the low pressure region. C at 298K, measured at 0.025 bar and 1 bar respectively₂H₂The absorptions of (a) were 2.1 mmol/g and 3.8 mmol/g. Under the same conditions, C was measured₂H₄The absorption was only 0.17 mmol/g and 2.1 mmol/g. By using Clausius-Clapeyron equation, C₂H₂The equivalent heat (adsorption energy-Qst) was calculated to be 49.2 kJ/mol, which is much higher than C₂H₄34.2 kJ/mol as shown in FIG. 8B.

Powder X-ray diffraction (PXRD) and stability data

SNFSIX-2-Cu-i prepared according to the above method was tested for stability to humidity by exposing SNFSIX-2-Cu-i to 75% humidity and 40 ℃ for 14 days. The PXRD pattern of the sample after humidity testing (see fig. 9A) was the same as the PXRD pattern obtained for the original sample (before humidity testing). C of exposed and original sample₂H₂The isotherm (FIG. 9B) shows that SNFSIX-2-Cu-i is stable to humidity and its adsorption behavior is not affected by exposure to humidity.

Example 4: SIFIX-3-Ni

Synthesis of SIFSIX-3-Ni

0.32 g pyrazine (4 mmol) and 0.62 g NiSiF₆∙6H₂O (2 mmol) was added to 3 ml H₂O, and the suspension is stirred for several days. The resulting purple microcrystalline solid SIX-3-Ni was harvested by filtration.

Structure of (1)

SIFIX-3-Ni is a 3D hybrid porous material of pristine cubic topology. In this structure, the metal cation and pyrazine ligand are generated from SiF₆ ^2-A 2D layer of anionic pillared (see fig. 10A and 10B). The structure includes a 1D channel hole having an effective aperture diameter of about 3.7 a. Inorganic column SiF₆ ^2-Exposed to the inner surface of the hole and promoting the reaction with C₂H₂Strong interaction of (a).

Pure gas adsorption study

C collecting SIFSIX-3-Ni at 273K and 298K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 11A, SIFSIX-3-Ni vs. C₂H₂Absorption ratio of C₂H₄More particularly in the low pressure region. C at 298K, measured at 0.025 bar and 1 bar respectively₂H₂The absorptions of (a) were 0.77 mmol/g and 3.3 mmol/g. Under the same conditions, C was measured₂H₄Absorption was only 0.05 mmol/g and 1.75 mmol/g. By using the Clausius-Clapeyron equation, C₂H₂The equivalent heat (adsorption energy-Qst) was calculated to be 36.7 kJ/mol, which is much higher than C₂H₄31.6 kJ/mol as shown in FIG. 11B.

Powder X-ray diffraction (PXRD) and stability data

SIFIX-3-Ni prepared according to the above method was tested for stability to humidity by exposing SISISIX-3-Ni to 75% humidity and 40 ℃ for 1 day, 7 days and 14 days. The PXRD pattern of the sample after humidity testing (see fig. 12A) was the same as the PXRD pattern obtained for the original sample (before humidity testing). C of exposed and original sample₂H₂The isotherm (see fig. 12B) shows that SIFSIX-3-Ni is stable to humidity and its adsorption behavior is not affected by exposure to humidity.

Example 5: SIFIX-1-Cu

Synthesis of SIFSIX-1-Cu

0.35 g of 4,4' -bipyridine was dissolved in 40 ml of ethylene glycol at 65 ℃. Cu (BF) was added before heating the mixture at 65 ℃ for 3 hours under stirring₄)₂•xH₂O (266 mg, 1.12 mmol) and (NH)₄)₂SiF₆An aqueous solution (20 ml) (199 mg, 1.12 mmol) was added to the above solution. The resulting purple powder was filtered, washed with methanol and exchanged with methanol for 3 days.

Structure of (1)

SIFIX-1-Cu is a 3D hybrid porous material in which metal cations and 4,4' -bipyridine ligands create a 2D square lattice network, which is formed from SiF₆ ^2-3D original cubic network of anionic struts (see fig. 13). The 3D mixed porous material is provided with an effective pore diameter of about 8a and alongcHole repeat distance of shaft (from Cu-SiF)₆-Cu bond, i.e. M-L²-M bond is defined) is a pore from 7A to 8A. Inorganic column SiF₆ ^2-Exposed to the inner surface of the hole and promoted with C₂H₂Strong interaction of (a).

Pure gas adsorption study

C collecting SIFSIX-1-Cu between 283K and 313K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 14A, SIFSIX-1-Cu showed high acetylene uptake (8.5 mmol/g) at 298K and 1.0 bar. C of SIFSIX-1-Cu₂H₂Absorption is the highest reported with MOFs and other porous adsorbents. Under the same conditions, only 4.1 mmol/g C was adsorbed on SIFSIX-1-Cu₂H₄(see FIG. 14B). C is calculated by using the Clausius-Clapeyron equation₂H₂And C₂H₄And is shown in fig. 15. C of SIFSIX-1-Cu₂H₂Qst (37 kJ/mol) of is much higher than C₂H₄Qst (19.7 kJ/mol).

Powder X-ray diffraction (PXRD)

FIG. 16 shows a PXRD pattern for SIFSIX-1-Cu.

Example 6: SIFIX-2-Cu

Synthesis of SIFSIX-2-Cu

A solution of 4,4' -bipyridinylacetylene (0.115 mmol) in ethanol (2.0 ml) was carefully layered on CuSiF₆•xH₂O (0.149 mmol) in ethylene glycol (2.0 ml). Two weeks later crystals of SIFSIX-2-Cu were obtained. The samples obtained were exchanged with ethanol for 4 days.

Structure of (1)

SIFSIX-2-Cu is a 3D hybrid porous material with a pristine-cubic coordination network with square channels (pores) as shown in fig. 17. The metal cation and the 4,4' -bipyridyl acetylene ligand produce a 2D square lattice network, which is formed from SiF₆ ^2-A 3D network of the original cubic topology of the anionic struts. The channel comprises an effective pore diameter of about 10.5A and is alongcHole repeat distance of shaft (from Cu-SiF)₆-Cu bond, i.e. M-L²-M bond definition) is a pore of about 10.5 a. Inorganic post SnF₆ ^2-Exposed to the inner surface of the hole and promoting the reaction with C₂H₂The interaction of (a).

Pure gas adsorption study

C collecting SIFSIX-2-Cu between 283K and 303K₂H₂And C₂H₄Adsorption isotherms. As shown in FIGS. 18A and 18B, SIFSIX-2-Cu pairs C₂H₂And C₂H₄Both exhibit a type II isotherm in which C is at 298K and 1.0 bar₂H₂The absorption was 5.38 mmol/g. Under the same conditions, SIFSIX-2-Cu absorbed only 2.02 mmol/g of C₂H₄。

FIG. 19 shows C of SIFSIX-2-Cu₂H₂And C₂H₄Adsorption energy (Qst).

Powder X-ray diffraction (PXRD)

FIG. 20 shows a PXRD pattern for SIFSIX-2-Cu.

Example 7: SIFSIX-3-Zn

Synthesis of SIFSIX-3-Zn

A solution of pyrazine (1.3 mmol) in methanol (2.0 ml) was carefully layered over ZnSiF₆• xH₂O (0.13 mmol) in methanol (2.0 ml). Two days later, colorless crystals of SIFSIX-3-Zn were obtained. The samples obtained were exchanged with ethanol for 1 day.

Structure of (1)

SIFSIX-3-Zn is a 3D hybrid porous material with a pristine-cubic coordination network with square channels (pores) as shown in figure 21. The metal cation and pyrazine ligand produce a 2D square lattice network, which is formed of SiF₆ ^2-A 3D network of the original cubic topology of the anionic struts. The channel has an effective pore diameter of about 4.2A and is alongcHole repeat distance of shaft (from Zn-SiF)₆-Zn bond, i.e. M-L²-M bond definition) is a pore of 4.2 a. Inorganic post SnF₆ ^2-Exposed to the pore surface and promoted with C₂H₂Strong interaction of (a).

Pure gas adsorption study

Collecting SIFSIX-3-Zn C at 283K and 398K₂H₂And C₂H₄Adsorption isotherms. As shown in FIG. 22A, SIFSIX-3-Zn absorbed 1.56 mmol/g and 3.6 mmol/g C at 0.025 bar and 1 bar, respectively₂H₂. Under the same conditions, only 0.196 mmol/g and 2.24 mmol/g C were measured₂H₄And (4) absorbing.

FIG. 22B shows C of SIFSIX-3-Zn₂H₂Adsorption energy (Qst).

Powder X-ray diffraction (PXRD)

FIG. 23 shows a PXRD pattern for SIFSIX-3-Zn.

Example 8: penetration test (breakthrough testing) was performed on the gas mixture

Purchasing gas as C₂H₂And C₂H₄The authentication mixture of (1). For the purposes of this example, the term "gas I" is used to denote a gas consisting of 1% C₂H₂And 99% of C₂H₄Gas mixture of constituents, and the term "gas II" is used to indicate a mixture of 50% C₂H₂And 50% of C₂H₄The resulting gas mixture. The flow rate was monitored using a mass flow controller and maintained at 1.25 ml/min. The experiment was carried out at 25 ℃. The outlet from the column was monitored using gas chromatography with Flame Ionization Detector (FID) (GC-8A, SHIMADZU). The concentration of the authentication mixture is used to calibrate the concentration of the outlet gas.

All experiments were performed using stainless steel tubing columns (internal diameter 4.6 mm x 50 mm). The weights packed in the column were as follows, depending on the different particle sizes and densities of the sample powders: 0.23 g of SIFSIX-1-Cu powder, 0.19 g of SISIX-2-Cu-i and 0.78 g of SISIX-3-Zn. The sample was first purged with a flow of He (15 ml/min) at room temperature (25 ℃) for 12 hours. A stream of the gas mixture (gas II) was then introduced at a rate of 1.25 ml/min. After the breakthrough experiment, the samples were regenerated with a flow of He (15 ml/min) for about 20 hours. The breakthrough test of gas I was then carried out at 25 ℃ on a packed bed of SIFSIX-1-Cu, SISIX-2-Cu-I or SISIX-3-Zn. The penetration curves recorded are shown in fig. 24A and 24B. The x-axis is the ratio of acetylene in the gas eluted from the column to the acetylene fraction in the starting gas (gas I or gas II) and the y-axis is time. These breakthrough tests measure the time taken for ethylene and acetylene to pass through a column containing each porous material. The longer the transit time of acetylene compared to ethylene, the better the separation.

FIG. 24A shows gas I (1% C) for SIFSIX-1-Cu, SISISIX-2-Cu-I and SISIX-3-Zn₂H₂，99% C₂H₄) The penetration curve of (c). Drawing (A)24B shows gas II (50% C) for SIFSIX-1-Cu, SISIX-2-Cu-i and SISIX-3-Zn₂H₂，50% C₂H₄) The penetration curve of (c).

The penetration curves of FIGS. 24A and 24B illustrate 1/99 and 50/50C₂H₂/C₂H₄High-efficiency separation is realized. 1/99 the mixture has a penetration time scale of SIFIX-2-Cu-i> SIFSIX-1-Cu >SISIFIX-3-Zn, and 50/50 the mixture has a penetration time rating of SISISIX-1-Cu> SIFSIX-3-Zn >SIFIX-2-Cu-i. From 50/50C during the dynamic penetration process, SIFIX-1-Cu, SISIX-2-Cu-i and SISIX-3-Zn₂H₂/C₂H₄(gas II) mixture trapped C₂H₂The amounts of (B) were 6.37 mmol/g, 2.88 mmol/g and 1.52 mmol/g, respectively. These results indicate that the inventive method using the mixed porous material described herein can provide efficient and selective separation of acetylene from a gas mixture at ambient conditions.

Example 9: breakthrough testing of gas mixtures

Penetration measurements were also performed to compare the mixed porous materials of the present invention with known reference materials (Fe-MOF-74 and UTSA-100 a). As shown in FIG. 25A, SIFSIX-3-Zn, SISIX-1-Cu and SISIX-2-Cu-i were unexpectedly superior to all other materials.

FIG. 25B is a plot of absorption versus selectivity at low pressure acetylene (0.01 atm). When acetylene is a minor component of the gas mixture (as is the case with purified ethylene), these conditions are related to the capture of acetylene. The more towards the upper right hand corner of the figure, the better the material. The three hybrid porous materials of the present invention show much higher selectivity than previously seen materials and they show excellent absorption. For example, Fe-MOF-74 is substantially non-selective even with high absorption. This is because Fe-MOF-74 strongly chemically bonds both ethylene and acetylene (chemisorption), whereas our material uses physical forces (physisorption) to capture acetylene. It is unprecedented and surprising to see such strong selectivity for physical forces.

₂ ₂ ₂Example 10: CH/CO separation

From equimolar amounts of C₂H₂/CO₂CO removal from gas mixtures₂The impurity is to obtain high purity C₂H₂As an important industrial process starting material for many chemical products. Taking into account pure C₂H₂Strict process pressure limits (below 2 bar) and C₂H₂And CO₂Is considered to be more similar than other separations such as C₂H₂/C₂H₄、CO₂/CH₄And CO₂/N₂Is more challenging. FIGS. 26A, 26B, 26C show pure gases C of SIFIX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i, respectively₂H₂And CO₂Adsorption data. FIG. 27 shows the adsorption energies (Qst) of SIFSX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i, and FIG. 28 shows the IAST selectivities of SIFSX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i.

C of SIFIX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i were collected at 273K and 298K₂H₂And CO₂Adsorption isotherms. As shown in FIGS. 26A-C, all three materials exhibited a pair C in the low pressure region₂H₂Absorption ratio of (2) to CO₂Is more absorbed. Measurement of the Pair C at 0.025 bar for SIFSX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i at 273K₂H₂The absorptions of (A) were 2.9 mmol/g, 3.0 mmol/g and 2.9 mmol/g, respectively. Under the same conditions, CO was measured₂The absorptions were only 1.4 mmol/g, 1.7 mmol/g and 1.1 mmol/g. By using Clausius-Clapeyron equation, C at low load of 52.7 kJ/mol, 46.3 kJ/mol and 49.2 kJ/mol were obtained for SISIX-2-Cu-i, TIFSIX-2-Cu-i and SNFSIX-2-Cu-i, respectively₂H₂An equivalent heat of CO at low load higher than 40.5 kJ/mol, 42.2 kJ/mol and 42.1 kJ/mol, respectively₂And (5) carrying out isothermal heating. Calculated based on the Ideal Adsorption Solution Theory (IAST), the SIFIX-2-Cu-i selectivity to the equimolar mixture was about 3 at 1 bar and 293K, showing a selectivity for C₂H₂Is superior to CO₂Selective adsorption of (3).

In summary, the invention is not limited to the embodiments described aboveThe present invention provides a method for separating acetylene from a gas mixture comprising acetylene. The method involves the use of a hybrid porous material having an affinity for acetylene adsorption. The hybrid porous material comprises a metal species (M) and a first linking group (L)¹) And a second linking group (L)²) Wherein the metal species (M) is linked via a first linking group (L)¹) Are linked together in a first and a second orientation and via a second linking group (L)²) Are joined together in a third direction to form the three-dimensional structure. The hybrid porous material may have a high selectivity for acetylene and/or a high acetylene adsorption capacity. The process may be particularly useful for purifying ethylene gas contaminated with acetylene, for example, during an ethylene production/purification process. The method may be particularly useful for separating acetylene on a relatively large scale from other gases such as ethylene and carbon dioxide, for example, during an acetylene production/purification process.

Claims

1. A method of separating acetylene from a gas mixture comprising acetylene, the method comprising contacting the gas mixture with a mixed porous material;

wherein the mixed porous material comprises a three-dimensional lattice of a metal species M and a linking group;

wherein the metal species M is linked through a first linking group L¹Linked together in a first dimension and a second dimension and via a second linking group L²Connected together in a third dimension to form a three-dimensional lattice;

wherein L is¹And L²Is an organic linking group, and L¹And L²Is an inorganic linking group; and is

Wherein the gas mixture is a gas mixture comprising acetylene and ethylene and/or a gas mixture comprising acetylene and carbon dioxide and/or a gas mixture comprising acetylene, ethylene and carbon dioxide.

2. The method of claim 1, wherein the hybrid porous material has the following formula:M(L¹)₂(L²)。

3. a process according to claim 1 or 2, wherein the metal species M and the linking group L¹And L²Comprises repeating structural units (I):

(I)。

4. the method according to claim 1 or 2, wherein the metal species M is selected from atoms or ions of Cu, Zn and Ni.

5. The method according to claim 1 or 2, wherein the first linking group L¹Is an organic linking group.

6. The method according to claim 5, wherein the first linking group L¹Is a doubly linked nitrogen ligand.

7. The method according to claim 6, wherein said first linking group L¹Is a doubly linked nitrogen ligand selected from the group consisting of pyrazine, 4 '-bipyridine and 4,4' -bipyridinylacetylene.

8. A method according to claim 1 or 2, wherein the second linking group L²Containing at least one fluorine atom.

9. A method according to claim 1 or 2, wherein the second linking group L²Is of the formula AX_n ^y-Wherein X is selected from F or Cl, n is an integer from 2 to 6, y is an integer from 0 to 2, and A is selected from Si, Ti, Sn, Zr or Ge.

10. The method according to claim 1 or 2, wherein the metal species M is selected from Cu²⁺、Ni²⁺And Zn²⁺Ion, the first linking group L¹Selected from the group consisting of 4,4 '-bipyridinylacetylene, 4' -bipyridine and pyrazine, and the second linking group L²Selected from SiF₆ ^2-、TiF₆ ^2-And SnF₆ ^2-Ions.

11. The method of claim 1 or 2, wherein the mixed porous material comprises pores having an effective pore diameter from 3.5A to 12A.

12. The method according to claim 1 or 2, wherein the gas mixture comprises an acetylene to ethylene ratio of from 0.1:99.9 to 10: 90.

13. The method according to claim 1 or 2, wherein the gas mixture comprises an acetylene to ethylene ratio of 4:6 to 9: 1.

14. The method according to claim 1 or 2, wherein the contacting of the gas mixture with the mixed porous material is performed at a temperature of-20 ℃ to 60 ℃.

15. The method according to claim 1 or 2, wherein the contacting of the gas mixture with the mixed porous material is performed at a pressure of 0.5 bar to 2 bar.

16. Use of a hybrid porous material for separating acetylene from a gas mixture comprising acetylene;

17. A hybrid porous material comprising a three-dimensional lattice of a metal species M and a linking group;

wherein the metal species M is linked through a first linking group L¹Linked together in a first dimension and a second dimension and via a second linking group L²Are connected together in a third dimension to form the three-dimensional lattice,

wherein the metal species M is linked through a first linking group L¹Linked together in a first dimension and a second dimension and via a second linking group L²Connected together in a third dimension to form the three-dimensional lattice;

wherein the first linking group L¹Is an organic linking group;

wherein the second linking group L²Is of the formula AX_n ^y-Wherein X is selected from F or Cl, n is an integer from 2 to 6, y is an integer from 0 to 2, and A is selected from Ti, Sn, Zr or Ge; and is

Wherein the metal species M and the linking group L¹And L²The three-dimensional lattice of (a) is interpenetrating.